Internal fastenings for joints



June 2, 1964 H. CHILTON 3,135,536

INTERNAL FASTENINGS FOR JOINTS Filed April 17, 1961 5 Sheets-Sheet 1 HARRY 0/11. TOIV anus 5y H/LDA 70AM CHILTJN EXE rR/x June 2, 1964 H. CHILTON 3,135,536

INTERNAL FASTENINGS FOR JOINTS Filed April 17, 1961 5 Sheets-Sheet 2 I/VVIA/TO 1? v HARRY c/msra 8y HILDA JOA/l 47m A/ B COTRIX an m June 2, 1964 1-1, CHILTON 3,135,536

INTERNAL FASTENINGS FDR JQINTS Filed April 17, 1961 5 SheetsSheet 3 FIG. 5

June 2, 1964 1-1. CHILTON 3,135,535

INTERNAL FASTENINGS FQR JOINTS Fil'd April 17, 1961 5 Sheets-Sheet 4 ,ay V

June 2, 1964 H. CHILTON 3,135,536

INTERNAL FASTENINGS FOR JOINTS Filed April 17, 1961 5 Shee cS-Sheet 5 United States Patent 3,135,536 FNTERNAL FASTENINGS FOR JOINTS Harry Chilton, deceased, late of Ewell, England, by Hilda .l'oan (Ihilton, executrix, Eweli, England, assignor to United Kingdom Atomic Energy Authority, London,

England Filed Apr. 17, 1961, Ser. No. 103,957 9 Claims. (Cl. 285-187) This invention relates to clamping means for use with coplanar joints and is an improvement in the invention described in our copending patent application No. 789,- 954 filed January 29, 1959.

The copending invention is concerned with joints in which the tendency for the joint surfaces to move relatively in the axial direction due to differences in the thermal expansion coefficients of the materials involved is minimized by applying clamping pressure to one member of the joint substantially in the contact plane of the surfaces.

With the type of joint described in the copending invention, it is understood that all parts of the joint assembly must be kept at the same temperature. This may be done by suitable installation and adequate lagging. However difidculties may arise if there are sudden temperature changes in the fluid being conveyed through the joint. This would produce unequal temperature distribution and subject the joint to thermal shock.

It is an object of the present invention to provide clamping means for coplanar joints, whereby the thermal effect on the joint due to a sudden change in the temperature of the conveyed fluid is minimized.

According to the present invention a joint between two hollow members comprises plane surfaces thereof held in contact by internal clamping means having a thermal expansion coefficient different from at least one of said members, the clamping pressure being applied to said one member substantially in the contact plane of said surface and wherein said clamping means is arranged within at least one of said members so as to be contacted by uid flow through the member.

To enable the nature of the present invention to be more readily understood attention is directed by way of example to the accompanying drawings wherein:

P16. 1 is a sectional elevation of a pipe joint.

FIG. 2 is a sectional plan on the line iI-II of FIG. 1.

FIG. 3 is a sectional elevation of another pipe joint.

FIG. 4 is a sectional plan on the line IV-IV of FIG. 3.

FIG. 5 is a sectional elevation of spigot and socket type of pipe joint.

FIG. 6 is a sectional plan on the line Vl-VI of FIG. 5.

FIG. 7 is a sectional elevation of a flanged pipe joint.

FIG. 8 is a sectional plan on the line VIII-VIII of FIG. 7.

FIG. 9 is a sectional elevation of a further flanged pipe oint.

PEG. 10 is a sectional plan on the line XX of FIG. 9.

FIGS. 1 and 2 show a pipe joint in which the lapped end surface of a steel pipe 1 and a graphite pipe 2 meet in a sealing plane YY. Pipe 1 has an integral steel spider-like member 3 located withint he bore a short distance from its lapped end surface. Said member 3 has a central boss portion which is axially bored to receive a steel clamping bolt 4.

A graphite spider-like member 5 having a projecting central boss is held in screwed relationship within the bore of pipe 2. The boss, which is arranged to project past the lapped end surface of the pipe, is axially bored and counterbored for a portion of its length to receive the shank and head portions of bolt 4, the contact plane between the undersurface 4 of the head of bolt 4 and the member 5 being arranged coplanar with sealing plane Y-Y.

The point is drawn together by tightening a clamping nut 7 on to bolt 4. The bolt 4 is held in place during assembly by nut 6. If the joint is to be operated at temperatures much higher than those in which it is assembled, the nut 6 can be tightened during assembly and need not be loosened before being used. However if the joint is to be operated at temperatures lower than those at which assembled, then preferably the nut 6 should not be screwed tightly against the bottom surface of spider 5, or alternatively the nut 6 should be backed 0d a few turns to provide a slight clearance between nut 6 and the bottom surface of graphite spider 5, as shown in FIG. 1.

In FIGS. 3 and 4 a modified form of joint construction is shown in which a large surface area of the clamping bolt is arranged to make intimate contact with the fluid conveyed through the joint.

Referring to FIGS. 3 and 4 the lapped end surfaces of a steel pipe 8 and a graphite pipe 9 meet in the plane YY. Pipe 8 has integral steel spider-like member 19 located within the bore a short distance from the lapped end surface. Said member 10 has a central boss which is axially bored to receive a steel clamping bolt 11.

A spider member 12 integrally located within the bore of pipe 9 comprises a central boss 13 and an apertured web portion 14. The main flow for the fluid passing through the joint is via the apertures 15 formed in web 14. Boss 13, the end of which projects past the end surface of pipe 9, is bored to receive the shank of bolt 11 and to provide a secondary annular flow passageway 16 around said bolt. The head of bolt 11, accommodated in a counterbore formed in boss 13, is provided with segmental flow ports 17 which complete the secondary flow passageway. The secondary flow thus contacts bolt 11 throughout the major part of its length. Bolt 11 is retained by a steel pin 18 inserted diametrically through the bolt to engage cooperating holes in boss 13. As shown in FIG. 3, preferably the pin 18 has some clearance in the holes in boss 13 so as not to hinder the expansion or contraction of bolt 11.

The contact plane 11 between the undersurface of the head of bolt 11 and boss 13 is formed coplanar with plane YY and the joint is drawn together by tightening a clamping nut 19 on to bolt 11.

A joint suitable for use with pipes formed from materials which may be unsuitable for the fabrication of fastening means and which may have similar or dissimilar coeflicients of expansion is described with reference to FIGS. 5 and 6. I

FIGS. 5 and 6 show a spigot and socket joint formed between two graphite pipes 43 and 44, the sealing plane being again YY. Pipe 44 has an inwardly directed lip 45, the undersurface of which is coplanar with plane YY.

An integral spider member 47 located near to the end of pipe 43, has a central boss 48 which projects into pipe 44. Said boss 43 is axially bored and counterbored to receive and accommodate the head 49 of a steel clamping bolt 50, the contactplane 51 between the undersurface of said head 49 and boss 48 being arranged to lie in the plane YY. I

Located within the bore of pipe 44 is a steel spider member 52. Said member 52 has a central boss 53 which is axially bored and threaded to receive the end of bolt 50 and an upstanding outer rim 54 adapted to engage lip 45.

When bolt 50 is tightened the pipes 43 and 44 are drawn together, the clamping pressures being exerted on surfaces 51 and 46 by bolt head 49 and rim 54 respectively.

In the joints hereinbefore described with reference to FIGS. 1 and 2, 3 and 4, and 5 and 6, the clamping bolt and mountings are required to carry the sum of the pressure loading and the face sealing load, and thus may be assumed to be most suitable for low or negative pressure applications. The particular embodiments hereinafter described are more suitable for high pressure applications, in that the load on the clamping means is the difference between the face sealing load and the pressure load.

FIGS. 7 and 8 show a joint formed between a steel pipe 29 and a graphite pipe 21, the sealing plane again being YY. Pipe 21 has an outwardly directed lip 22 adapted to enter the bore of pipe and the co-operating end of pipe 20 is formed with an inwardly directed lip 23 engageable with lip 22.

An integral graphite spider member having a central boss 25 is located within the bore of pipe 21. A centralizing socket 26 is formed in the upper face of boss 25, the said upper face being coplanar with plane YY.

A steel spider member 27 held in threaded relationship within the bore of pipe 20 has a central boss 28 which is axially bored and threaded to receive a steel screw 29. The lower end of said screw 29 is formed with a spheric surface 30 to engage the spherical shaped upper end of a steel compression member 31 interposed between said screw 29 and boss 25. The lower end of member 31 is provided with a thrust shoulder 3% and a centralizing spigot 31, said spigot being adapted to enter socket 26 and act as a guide.

Tightening of screw 29 forces shoulder 30* against the upper face of boss 25, thus drawing lips 22 and 23 together forming a seal.

An alternative form of joint between lip ended pipes is shown if FIGS. 9 and 10 wherein a steel pipe 32 is sealed to a zircalloy pipe 33 on a plane YY.

An apertured plug member 34 is located within the bore of pipe 33 so that its end surface 35 is coplanar with plane YY. Member 34, is integral with pipe 33 and has a large central aperture 36 which forms part of the major fiow path through the joint. A plurality of segmental flow ports 37, which provide a secondary flow path through member 34 are formed in a concentric ring between the central aperture 36 and the interior surface of pipe 33.

A steel apertured plug 38 held in threaded relationship within the bore of pipe 32 is penetrated by a large central aperture 39 and a concentric ring of close pitched holes 4% drilled around said aperture 39. The lower edge 41 of aperture 39 is adapted to form a spheric shaped seat for the spherical upper edge of a hollow steel compression member 42 interposed between plug 38 and the upper surface 35 of member 34.

Fluid flowing through the joint is divided into a primary and a secondary flow, the primary via aperture 36, the interior of member 41, and aperture 39 and the secondary flowing through ports 37, the annular space between pipe 32 and member 41, and holes 40. The clamping means are thus intimately contacted by the fluid throughout their length.

The joint is drawn together by tightening plug 49 down on to the member 42, the resultant pressure being transferred through surface 35, to the pipe lips to form a seal in the plane YY.

The preferred mode of assembly for each of the joints described is to form the joint between stub ends of pipes of dissimilar materials, the joints being assembled, tightened, and tested, and subsequently inserted in the pipe line, only connecting each end of the joint to pipes of a similar composition, and using a conventional method of connection.

Alternatively the joint can be installed adjacent a bend having an access plate, which would facilitate tightening.

What is claimed is:

1. A coupling for joining two hollow members of substantially tubular form, comprising: a first hollow member of substantially tubular form comprised of a material having a given thermal coefficient and having a planar surface adjacent its end; a second hollow member of corresponding shape having a planar surface adjacent its end for matingly engaging the planar surface of said first member; means having a different coeificient of thermal expansion than one of said members and arranged within one of said members and in engagement therewith for holding said two planar surfaces in mating engagement irrespective of temperature changes within the coupling, said means comprising a force transmitting member so disposed with respect to said planar surfaces to apply force to one of said tubular members substantially in the plane of contact of said planar surfaces in a direction to maintain said surfaces in intimate engagement and a second member in engagement with said force transmitting member and with the other hollow member arranged to apply an oppositely directed force to the other of said tubular members on a plane on the said other tubular member, said plane being so located relative to said planar surfaces and the thermal expansion coefficient of said force transmitting member being such that any change in length in said other tubular member between its planar surface and said plane is accompanied by a corresponding change in length in said force transmitting member.

2. Apparatus as set forth in claim 1 wherein said force transmitting member has a thermal expansion cocfiicient equal to said second hollow member, and said point is located at a distance from said planar surfaces.

3. Apparatus as set forth in claim 1 wherein said plane is located in the plane of said planar surfaces.

4. Apparatus as set forth in claim 1 wherein said planar surfaces are formed on flanges facing oppositely from the respective ends of said tubular members, and said force transmitting member is a compression member, said plane being spaced from said planar surfaces, the thermal expansion coefficient of said force transmitting member being equal to the thermal expansion coefficient of the said other member at least over the distance between said planar surfaces and said plane.

5. Apparatus as set forth in claim 1 wherein said force transmitting member comprises a tension member bearing against a portion of one of said members substantially in the plane of contact of said planar surfaces, said tension member extending axially into the interior of the other of said members, said second member being a compression member connected to the extended end of said tension member and bearing against a portion of the other of said members substantially in the plane of contact of said planar surfaces, said tension and compression members being of substantially equal effective length and having substantially equal thermal expansion coefficients.

6. Apparatus as set forth in claim 5 further comprising means for adjusting said tension member relative to said compression member in a direction substantially normal to said planar surfaces.

7. Apparatus as set forth in claim 6 wherein said compression member comprises a spider member having a threaded central boss and said tension member comprises a bolt having a threaded portion inserted in said threaded central boss.

8. Apparatus as set forth in claim 4 wherein said compression member is hollow, the interior thereof forming a primary flow passageway, and an annular space around the exterior of said compression member forming a secondary flow passageway through the joint.

9. A pipe coupling comprising two pipes having planar surfaces normal to their axes adjacent their ends in abutting engagement, an internal spider member formed integral with one pipe adjacent its abutting surface, said spider having an axially extending boss thereon, a bore extending axially through said boss, a counter bore in the inner end of said boss terminating in a shoulder normal to the boss axis, said shoulder and said abutting surfaces lying in a single plane transverse to the pipe axis, a lip formed integral with the end of the other pipe, said lip a extending radially inward and being inserted into the end References Cited in the file of this patent of said one pipe, the axially inner surface of said lip being UNITED STATES PATENTS normal to the pipe axis, a second spider having a threaded central boss and an outer rim, said rim engaging said inner 1'603241 McLean 1926 surface of said lip, the engaging surfaces of said rim 5 2,824,758 Camel} 1958 and lip lying in said single plane, a bolt inserted through FOREIGN PATENTS said bore with the bolt head abutting said shoulder, the

other end of said bolt threaded into said threaded boss, 807336 Great Bntam 1959 1,216,046 France Nov. 23, 1959 and sand bolt and said second spider having the same coefficient of thermal expansion. 10 

1. A COUPLING FOR JOINING TWO HOLLOW MEMBERS OF SUBSTANTIALLY TUBULAR FORM, COMPRISING: A FIRST HOLLOW MEMBER OF SUBSTANTIALLY TUBULAR FORM COMPRISED OF A MATERIAL HAVING A GIVEN THERMAL COEFFICIENT AND HAVING A PLANAR SURFACE ADJACENT ITS END; A SECOND HOLLOW MEMBER OF CORRESPONDING SHAPE HAVING A PLANAR SURFACE ADJACENT ITS END FOR MATINGLY ENGAGING THE PLANAR SURFACE OF SAID FIRST MEMBER; MEANS HAVING A DIFFERENT COEFFICIENT OF THERMAL EXPANSION THAN ONE OF SAID MEMBERS AND ARRANGED WITHIN ONE OF SAID MEMBERS AND IN ENGAGEMENT THEREWITH FOR HOLDING SAID TWO PLANAR SURFACES IN MATING ENGAGEMENT IRRESPECTIVE OF TEMPERATURE CHANGES WITHIN THE COUPLING, SAID MEANS COMPRISING A FORCE TRANSMITTING MEMBER SO DISPOSED WITH RESPECT TO SAID PLANAR SURFACES TO APPLY FORCE TO ONE SAID TUBULAR MEMBERS SUBSTANTIALLY IN THE PLANE OF CONTACT OF SAID PLANAR SURFACES IN A DIRECTION TO MAINTAIN SAID SURFACES IN INTIMATE ENGAGEMENT AND A SECOND MEMBER IN ENGAGEMENT WITH SAID FORCE TRANSMITTING MEMBER AND WITH THE OTHER HOLLOW MEMBER ARRANGED TO APPLY AN OPPOSITELY DIRECTED FORCE TO THE OTHER OF SAID TUBULAR MEMBERS ON A PLANE ON THE SAID OTHER TUBULAR MEMBER, SAID PLANE BEING SO LOCATED RELATIVE TO SAID PLANAR SURFACES AND THE THERMAL EXPANSION COEFFICIENT OF SAID FORCE TRANSMITTING MEMBER BEING SUCH THAT ANY CHANGE IN LENGTH IN SAID OTHER TUBULAR MEMBER BETWEEN ITS PLANAR SURFACE AND SAID PLANE IS ACCOMPANIED BY A CORRESPONDING CHANGE IN LENGTH IN SAID FORCE TRANSMITTING MEMBER. 